Kayak

A kayak is a small, narrow boat primarily designed to be manually propelled by means of a double-bladed paddle. The word kayak originates from the Greenlandic Inuktitut language, where it is the word 'qayaq'. In the UK the term canoe is often used when referring to a kayak.[1][2] The traditional kayak has a covered deck and one or more cockpits, each seating one paddler. The cockpit is sometimes covered by a spray deck that prevents the entry of water from waves or spray and makes it possible for suitably skilled kayakers to roll the kayak: that is, to capsize and right it without it filling with water or ejecting the paddler.

Some modern boats vary considerably from a traditional design but still claim the title "kayak", for instance in eliminating the cockpit by seating the paddler on top of the boat ("sit-on-top" kayaks); having inflated air chambers surrounding the boat; replacing the single hull by twin hulls ("W" kayak), and replacing paddles with other human-powered propulsion methods, such as foot-powered rotational propellers and "flippers". Kayaks are also being sailed, as well as propelled by means of small electric motors, and even by outboard gas engines, when possible.

Kayaks are often used to get closer to marine animals, for example sea otters

Native people made many types of boat for different purposes. The baidarka, developed by indigenous cultures in Alaska, was also made in double or triple cockpit designs, for hunting and transporting passengers or goods. An umiak is a large open sea canoe, ranging from 17 to 30 feet (5.2 to 9.1 m), made with seal skins and wood. It is considered a kayak although it was originally paddled with single-bladed paddles, and typically had more than one paddler.

Native builders designed and built their boats based on their own experience and that of the generations before them, passed on through oral tradition. The word "kayak" means "man's boat" or "hunter's boat", and native kayaks were a personal craft, each built by the man who used it—with assistance from his wife, who sewed the skins—and closely fitting his size for maximum maneuverability. A special skin jacket, Tuilik, was then laced to the kayak, creating a waterproof seal. This enabled the eskimo roll to become the preferred method of regaining posture after capsizing, especially as few Eskimos could swim; their waters are too cold for a swimmer to survive for long.[5]

Instead of a tuilik, most traditional kayakers today use a spray deck made of waterproof synthetic material stretchy enough to fit tightly around the cockpit rim and body of the kayaker, and which can be released rapidly from the cockpit to permit easy exit.

Eskimo kayak builders had specific measurements for their boats. The length was typically three times the span of his outstretched arms. The width at the cockpit was the width of the builder's hips plus two fists (and sometimes less). The typical depth was his fist plus the outstretched thumb (hitch hiker). Thus typical dimensions were about 17 feet (5.2 m) long by 20–22 inches (51–56 cm) wide by 7 inches (18 cm) deep. This measurement system confounded early European explorers who tried to duplicate the kayak, because each kayak was a little different.

Traditional kayaks encompass three types: Baidarkas, from the Bering sea & Aleutian islands, the oldest design, whose rounded shape and numerous chines give them an almost Blimp-like appearance; West Greenland kayaks, with fewer chines and a more angular shape, with gunwales rising to a point at the bow and stern; and East Greenland kayaks that appear similar to the West Greenland style, but often fit more snugly to the paddler and possess a steeper angle between gunwale and stem, which lends maneuverability.

Most of the Aleut people in the Aleutian Islands eastward to Greenland Inuit relied on the kayak for hunting a variety of prey—primarily seals, though whales and caribou were important in some areas. Skin-on-frame kayaks are still being used for hunting by Inuit people in Greenland, because the smooth and flexible skin glides silently through the waves. In other parts of the world home builders are continuing the tradition of skin on frame kayaks, usually with modern skins of canvas or synthetic fabric, such as sc. ballistic nylon.

Contemporary traditional-style kayaks trace their origins primarily to the native boats of Alaska, northern Canada, and Southwest Greenland. Wooden kayaks and fabric kayaks on wooden frames dominated the market up until the 1950s, when fiberglass boats were first introduced in the US, and inflatable rubberized fabric boats were first introduced in Europe. Rotomoldedplastic kayaks first appeared in 1973, and most kayaks today are made from roto-molded Poletheylene resins. The development of plastic and rubberized inflatable kayaks arguably initiated the development of freestyle kayaking as we see it today, since these boats could be made smaller, stronger and more resilient than fiberglass boats.

This Greenland paddle is 7 feet (2.1 m) in length, and much narrower than European paddles.

As a general rule, a longer kayak is faster. See Hull speed. Kayaks that are built to cover longer distances such as touring and sea kayaks are longer, generally 16 to 19 feet (4.9 to 5.8 m). With touring kayaks the keel is generally more defined (helping the kayaker track in a straight line.) Whitewater kayaks, which generally depend upon river current for their forward motion, are short, to maximize maneuverability. These kayaks rarely exceed 8 feet (2.4 m) in length, and play boats may be only 5–6 feet (1.5–1.8 m) long. Recreational kayak designers try to provide more stability at the price of reduced speed, and compromise between tracking and maneuverability, ranging from 9–14 feet (2.7–4.3 m).

Primary (sometimes called initial) stability describes how much a boat tips, or rocks back and forth, when displaced from level by paddler weight shifts. Secondary (final) stability describes how stable a kayak feels when put on edge or when waves are passing under the hull perpenducular to the length of the boat. Primary stability is often a big concern to a beginner, while secondary stability matters both to beginners and experienced travelers. By example, a wide, flat-bottomed kayak will have high primary stability and feel very stable on flat water. However, when a steep wave breaks on such a boat, it can be easily overturned because the flat bottom is no longer level. By contrast, a kayak with a narrower, more rounded hull can be edged or leaned into waves and (in the hands of a skilled kayaker) provides a safer, more comfortable response on stormy seas.

The most important attribute in determining the stability of a single hulled kayak is the overall width of its cross section. The shape of the cross section can affect both maneuverability and stability. Hull shapes are categorized by roundness/flatness, whether it has a "V" shape at various points, and by the presence and severity of a chine, where the side and bottom of a hull meet at an angle, creating an edge below the gunwales. This cross–section may vary along the length of the boat. Kayaks with only moderate primary, but excellent secondary stability are, in general, considered more seaworthy, especially in challenging conditions.

Conversely, flat-bottomed hulls are easy to turn, but harder to direct in a constant direction.

The chine typically increases secondary stability by effectively widening the beam of the boat when it heels (tips). Sea kayaks, designed for open water and rough conditions, are generally narrower 22–25 inches (56–64 cm) and have more secondary stability than recreational kayaks, which are wider 26–30 inches (66–76 cm), have a flatter hull shape, and more primary stability.

Length alone does not fully predict a kayak's maneuverability: a second design element is rocker, i.e. its lengthwise curvature. A heavily rockered boat curves more, shortening its effective waterline. For example, an 18-foot (5.5 m) kayak with no rocker is in the water from end to end. In contrast, the bow and stern of a rockered boat are out of the water, shortening its lengthwise waterline to only 16 ft (4.9 m). Rocker is generally most evident at the ends, and in moderation improves handling. Similarly, although a rockered whitewater boat may only be a few feet shorter than a typical recreational kayak, its waterline is far shorter and its maneuverability far greater. When surfing a heavily rockered boat is less likely to lock into the wave as the bow and stern are still above water. A boat with less rocker cuts into the wave and makes it harder to turn while surfing.

Some recreational kayak makers try to maximize hull volume (weight capacity) for a given length as shorter kayaks are easier to transport and store. Many paddlers who use a sit-in kayak feel more secure in a kayak with a weight capacity substantially more than their own weight. Maximum volume in a sit-in kayak is helped by a wide hull with high sides. But paddling ease is helped by lower sides where the paddler sits and a narrower width. A narrower kayak makes a somewhat shorter paddle appropriate and a shorter paddle puts less strain on the shoulder joints. Some paddlers are comfortable with a sit-in kayak so narrow that their legs extend fairly straight out. Others want sufficient width to permit crossing their legs inside the kayak. Traditional-style and most modern types of kayaks (e.g. sit-on-top) require that paddler be seated with their legs stretched in front of them, in a right angle, in a position called the "L" kayaking position. Most modern kayaks feature a system comprising footrests and a backrest, designed to provide the paddler with means to support their paddling effort by allowing them to push the footrests with their feet, and the backrest with their lower back (lumbar spine). Such arrangements were not included in kayaks made by native peoples of the arctic regions, who were fit enough to paddle their kayaks without needing such devices. These devices are not required in new twin hull kayaks of the "W" type that offer a different sitting position called the "Riding" position, in which the paddler's legs are not stretched out in front of them.

Today almost all kayaks are commercial products intended for sale rather than for the builder's personal use.

Fiberglass hulls are stiffer than polyethylene hulls, but they are more prone to damage from impact, including cracking. Most modern kayaks have steep V sections at the bow and stern, and a shallow V amidships. Fiberglass kayaks need to be "laid-up" in a mold by hand, so are usually more expensive than polyethylene kayaks, which are rotationally molded in a machine.

Plastic kayaks are rotationally molded ('rotomolded') from a various grades and types of polyethylene resins ranging from soft to hard. Such kayaks are particularly resistant to impact.

Wooden hulls don't necessarily require significant skill and handiwork, depending on how they are made. Kayaks made from thin strips of wood sheathed in fiberglass have proven successful, especially as the price of epoxy resin has decreased in recent years. A plywood, stitch and glue (S&G) doesn't need fiberglass sheathing though some builders do. Three main types are popular, especially for the home builder: Stitch & Glue, Strip-Built, and hybrids which have a stitch & glue hull and a strip-built deck.

Stitch & Glue designs typically use modern, marine-grade plywood — eighth-inch, 3 millimetres (0.12 in) or up to quarter-inch, 5 millimetres (0.20 in) thick. After cutting out the required pieces of hull and deck (kits often have these pre-cut), a series of small holes are drilled along the edges. Copperwire is then used to "stitch" the pieces together through the holes. After the pieces are temporarily stitched together, they are glued with epoxy and the seams reinforced with fiberglass. When the epoxy dries, the copper stitches are removed. Sometimes the entire boat is then covered in fiberglass for additional strength and waterproofing though this adds greatly to the weight and is unnecessary. Construction is fairly straightforward, but because plywood does not bend to form compound curves, design choices are limited. This is a good choice for the first-time kayak builder as the labor and skills required (especially for kit versions) is considerably less than for strip-built boats which can take 3 times as long to build.

Strip-built designs are similar in shape to rigid fiberglass kayaks but are generally both lighter and tougher. Like their fiberglass counterparts the shape and size of the boat determines performance and optimal uses. The hull and deck are built with thin strips of lightweight wood, often cedar, pine or Redwood. The strips are edge-glued together around a form, stapled or clamped in place, and allowed to dry. Structural strength comes from a layer of fiberglass cloth and epoxy resin, layered inside and outside the hull. Strip–built kayaks are sold commercially by a few companies, priced USD 4,000 and up. An experienced woodworker can build one for about USD 400 in 200 hours, though the exact cost and time depend on the builder's skill, the materials and the size and design. As a second kayak project, or for the serious builder with some woodworking expertise, a strip–built boat can be an impressive piece of work. Kits with pre-cut and milled wood strips are commercially available.

Skin on frame boats are more traditional in design, materials, and construction. They were traditionally made of driftwood, pegged or lashed together, and stretched seal skin, as those were the most readily available materials in the Arctic regions. Today, seal skin is usually replaced with canvas or nyloncloth covered with paint, polyurethane, or a hypalonrubber coating and a wooden or aluminum frame. Modern skin-on-frame kayaks often possess greater impact resistance than their fiberglass counterparts, but are less durable against abrasion or sharp objects. They are often the lightest kayaks.

A special type of skin-on-frame kayak is the folding kayak. It has a collapsible frame, of wood, aluminum or plastic, or a combination thereof, and a skin of water-resistant and durable fabric. Many types have air sponsons built into the hull, making the kayak float even if flooded.

Modern kayaks differ greatly from native kayaks in every aspect—from initial form through conception, design, manufacturing and usage. Modern kayaks are designed with CAD (Computer Aided Design) software, often in combination with CAD customized for naval design.

Modern kayaks serve diverse purposes, ranging from slow and easy touring on placid water, to racing and complex maneuvering in fast-moving whitewater, to fishing and long-distance ocean excursions. Modern forms, materials and construction techniques make it possible to effectively serve these needs while continuing to leverage the insights of the original Arctic inventors.

Modern kayaks have evolved into specialized types that may be broadly categorized according to their application as sea or touring kayaks, whitewater (or river) kayaks, surf kayaks, racing kayaks, fishing kayaks' and recreational kayaks. The broader kayak categories today are 'Sit-In', which is inspired mainly by traditional kayak forms, 'Sit-On-Top' (SOT), which evolved from paddle boards that were outfitted with footrests and a backrest, 'Hybrid', which are essentially canoes featuring a narrower beam and a reduced free board enabling the paddler to propel them from the middle of the boat, using a double blade paddle (i.e. 'kayak paddle'), and twin hull kayaks offering each of the paddler's legs a narrow hull of its own. In recent decades, kayaks design have proliferated to a point where the only broadly accepted denominator for them is their being designed mainly for paddling using a kayak paddle featuring two blades i.e. 'kayak paddle'. However, even this inclusive definition is being challenged by other means of human powered propulsion, such as foot activated pedal drives combined with rotating or sideways moving propellers, electric motors, and even outboard motors.

Recreational kayaks are designed for the casual paddler interested in fishing, photography, or a peaceful paddle on a lake, flatwater stream or protected salt water away from strong ocean waves. These boats presently make up the largest segment of kayak sales. Compared to other kayaks, recreational kayaks have a larger cockpit for easier entry and exit and a wider beam (27–36 inches (69–91 cm) for more stability. They are generally less than 12 feet (3.7 m) in length and have limited cargo capacity. Less expensive materials like polyethylene and fewer options keep these boats relatively inexpensive. Most canoe/kayak clubs offer introductory instruction in recreational boats. They do not perform as well in the sea. The recreational kayak is usually a type of touring kayak.[6]

Sea kayaks are typically designed for travel by one, two or even three paddlers on open water and in many cases trade maneuverability for seaworthiness, stability, and cargo capacity. Sea-kayak sub-types include "skin-on-frame" kayaks with traditionally constructed frames, open-deck "sit-on-top" kayaks, and recreational kayaks.

The sea kayak, though descended directly from traditional types, is implemented in a variety of materials. Sea kayaks typically have a longer waterline, and provisions for below-deck storage of cargo. Sea kayaks may also have rudders or skegs (fixed rudder) and upturned bow or stern profiles for wave shedding. Modern sea kayaks usually have two or more internal bulkheads. Some models can accommodate two or sometimes three paddlers.

Sealed-hull (unsinkable) craft were developed for leisure use, as derivatives of surfboards (e.g. paddle or wave skis), or for surf conditions. Variants include planing surf craft, touring kayaks, and sea marathon kayaks. Increasingly, manufacturers build leisure 'sit-on-top' variants of extreme sports craft, typically using polyethylene to ensure strength and affordability, often with a skeg for directional stability. Water that enters the cockpit drains out through scupper holes—tubes that run from the cockpit to the bottom of the hull.

Sit-on-top kayaks come in 1-4 paddler configurations. Sit-on-top kayaks are particularly popular for fishing and SCUBA diving, since participants need to easily enter and exit the water, change seating positions, and access hatches and storage wells. Ordinarily the seat of a sit-on-top is slightly above water level, so the center of gravity for the paddler is higher than in a traditional kayak. To compensate for the higher center of gravity, sit-on-tops are often wider and slower than a traditional kayak of the same length.

Contrary to popular belief, the sit-on-top kayak hull is not self bailing, since water penetrating it does not drain out automatically, as it does in bigger boats equipped with self bailing systems. Furthermore, the sit-on-top hull cannot be molded in a way that would assure water tightness, and water may get in through various holes in its hull, usually around hatches and deck accessories. If the sit-on-top kayak is loaded to a point where such perforations are covered with water, or if the water paddled is rough enough that such perforations often go under water, the sit-on-top hull may fill with water without the paddler noticing it in time.

Specialty surf boats typically have flat bottoms, and hard edges, similar to surf boards. The design of a surf kayak promotes the use of an ocean surf wave (moving wave) as opposed to a river or feature wave (moving water). They are typically made from rotomolded plastic, or fiberglass.

Surf kayaking comes in two main varieties, High Performance (HP) and International Class (IC). HP boats tend to have a lot of nose rocker, little to no tail rocker, flat hulls, sharp rails and up to four fins set up as either a three fin thruster or a quad fin[according to whom?]. This enables them to move at high speed and maneuver dynamically. IC boats have to be at least 3 metres (9.8 ft) long and until a recent rule change had to have a convex hull; now flat and slightly concave hulls are also allowed, although fins are not. Surfing on international boats tends to be smoother and more flowing, and they are thought of as kayaking's long boarding. Surf boats come in a variety of materials ranging from tough but heavy plastics to super light, super stiff but fragile foam–cored carbon fiber. Surf kayaking has become popular in traditional surfing locations, as well as new locations such as the Great Lakes.

Surf skis, are specialized narrow and long boats for racing, surfing breaking waves and surf-zone rescues.

A variation on the closed cockpit surf kayak is called a waveski. Although the waveski offers dynamics similar to a sit–on–top, its paddling technique and surfing performance and construction can be similar to surfboard designs.

Whitewater kayaks are rotomolded in a semi-rigid, high impact plastic, usually polyethylene. Careful construction ensures that the boat remains structurally sound when subjected to fast-moving water. The plastic hull allows these kayaks to bounce off rocks without leaking, although they scratch and eventually wear through with enough use. Whitewater kayaks range from 4 to 10 feet (1.2 to 3.0 m) long. There are two main types of whitewater kayak:

One type, the playboat, is short, with a scooped bow and blunt stern. These trade speed and stability for high maneuverability. Their primary use is performing tricks in individual water features or short stretches of river. In playboating or freestyle competition (also known as rodeo boating), kayakers exploit the complex currents of rapids to execute a series of tricks, which are scored for skill and style.

The other primary type is the creek boat, which gets its name from its purpose: running narrow, low-volume waterways. Creekboats are longer and have far more volume than playboats, which makes them more stable, faster and higher-floating. Many paddlers use creekboats in "short boat" downriver races, and they are often seen on large rivers where their extra stability and speed may be necessary to get through rapids.

Between the creekboat and playboat extremes is a category called river–running kayaks. These medium–sized boats are designed for rivers of moderate to high volume, and some, known as river running playboats, are capable of basic playboating moves. They are typically owned by paddlers who do not have enough whitewater involvement to warrant the purchase of more–specialized boats.

Squirt Boating involves paddling both on the surface of the river and underwater. Squirt boats must be custom-fitted to the paddler to ensure comfort while maintaining the low interior volume necessary to allow the paddler to submerge completely in the river.

White water racers combine a fast, unstable lower hull portion with a flared upper hull portion to combine flat water racing speed with extra stability in open water: they are not fitted with rudders and have similar maneuverability to flat water racers. They usually require substantial skill to achieve stability, due to extremely narrow hulls. Whitewater racing kayaks, like all racing kayaks, are made to regulation lengths, usually of fiber reinforced resin (usually epoxy or polyester reinforced with Kevlar, glass fiber, carbon fiber, or some combination). This form of construction is stiffer and has a harder skin than non-reinforced plastic construction such as rotomolded polyethylene: stiffer means faster, and harder means fewer scratches and therefore also faster.

Sprint kayak is a sport held on calm water. Crews or individuals race over 200 m, 500 m, 1000 m or 5000 m with the winning boat being the first to cross the finish line. The paddler is seated, facing forward, and uses a double-bladed paddle pulling the blade through the water on alternate sides to propel the boat forward. In competition the number of paddlers within a boat is indicated by a figure besides the type of boat; K1 signifies an individual kayak race, K2 pairs, and K4 four-person crews. Kayak sprint has been in every summer olympics since it debuted at the 1936 summer olympics.[7]racing is governed by the International Canoe Federation.

A specialized variant of racing kayak called a surf ski has an open cockpit and can be up to 21 feet (6.4 m) long but only 18 inches (46 cm) wide, requiring expert balance and paddling skill. Surf skis were originally created for surf and are still used in races in New Zealand, Australia, and South Africa. They have become popular in the United States for ocean races, lake races and even downriver races.

Inflatables, also known as the duckies or IKs, can usually be transported by hand using a carry bag. They are generally made of hypalon (a kind of neoprene), Nytrylon (a rubberized fabric), PVC, or polyurethane coated cloth. They can be inflated with foot, hand or electric pumps. Multiple compartments in all but the least expensive increase safety. They generally use low pressure air, almost always below 3 psi.

While many inflatables are non-rigid, essentially pointed rafts, best suited for use on rivers and calm water, the higher end inflatables are designed to be hardy, seaworthy vessels. Recently some manufacturers have added an internal frame (folding-style) to a multi-section inflatable sit-on-top kayak to produce a seaworthy boat.

The appeal of inflatable kayaks is their portability, their durability (they don't dent), ruggedness in white water (they bounce off rocks rather than break) and their easy storage. In addition, inflatable kayaks generally are stable, have a small turning radius and are easy to master, although some models take more effort to paddle and are slower than traditional kayaks.

Because inflatable kayaks aren't as sturdy as traditional, hard-shelled kayaks, a lot of people tend to steer away from them. However, there have been considerable advancements in inflatable kayak technology over recent years.[8]

Folding kayaks are direct descendants of the skin-on-frame boats used by the Inuit and Greenlandic peoples. Modern folding kayaks are constructed from a wooden or aluminum frame over which is placed a synthetic skin made of polyester, cotton canvas, polyurethane, or Hypalon. They are more expensive than inflatable kayaks, but have the advantage of greater stiffness and consequently better seaworthiness.

A kayak with pedals allows the kayaker to propel the vessel with a rotating propeller or underwater "flippers" rather than with a paddle. In contrast to paddling, kayakers who pedal kayaks use their legs rather than their arms.

Traditional multi-hull vessels such as catamarans and outrigger canoes benefit from increased lateral stability without sacrificing speed, and these advantages have been successfully applied in twin hull kayaks of the W type. Outrigger kayaks attach one or two smaller hulls to the main hull to enhance stability, especially for fishing, touring, kayak sailing and motorized kayaking. Twin hull kayaks feature two long and narrow hulls, and since all their buoyancy is distributed as far as possible from their center line, they are stabler than mono hull kayaks outfitted with outriggers.

While native people of the Arctic regions hunted rather than fished from kayaks, in recent years kayak sport fishing has become popular in both fresh and salt water, especially in warmer regions. Traditional fishing kayaks are characterized by wide beams of up to 42 inches (110 cm) that increase their lateral stability. Some are equipped with outriggers that increase their stability, and others feature twin hulls enabling stand up paddling and fishing. Compared with motorboats, fishing kayaks are inexpensive and have few maintenance costs. Many kayak anglers like to customize their kayaks for fishing, a process known as 'rigging'.

While paddling in the standing position has been practised for centuries in canoes (including Umiaks, Pirogues, and native dugout canoes) recently kayakers have attempted paddling while standing up, but so far, this has been made possible only in twin hull kayaks of the W type, mainly due to comfort and safety reasons.

^There is scant evidence of Ainu peoples using the classic kayak design in prehistoric times. the follosing indicates that they did use skin-covered vessels, however: "Like the yara chisei, bark houses, … yara chip, bark boats, were probably substitutes for the skin-covered boat, elsewhere surviving in the coracle and kayak. Skin-covered boats … are referred to in old [Ainu] traditions. -Ainu material culture from the notes of N. G. Munro: in the archive of the Royal Anthropological Institute, British Museum, Department of Ethnography, 1994 , p. 33